I will tell you another thing that dont make sense. I recently went for a trip to Italy and crossed over Switzerland with my RP. RP had a schengen visa..the border control officers looked at it and the GC and let me through. So i have no clue whats the real requirements are.
Also when I entered Germany with my RP and schengen visa..the officer didn't even look at the visa and stamped it. I told him about the visa and he told me RP doesn't need a visa to Germany...weird!
Obviously, the officer made a mistake.